ConQuest is only available as part of the Cambridge Structural Database (CSD) System which is released in November of each year. It is also possible to download data updates
at regular intervals between each major release. For further information on obtaining a copy please see Obtaining Products.
Which file formats
are available for saving search results?
Formats available for saving search results include: cif, Simulated SHELX, MDL sd file,
Tripos mol2 and CCDC fdat. Data can also be exported to plain text files and saved as a pdf file.
To save your search results select File from the top-level menu followed by Export Entries as... in the resulting pull-down menu.
From here it is possible to save the individual structure currently being displayed, or to save all unsuppressed structures
in the hit list.
Why has my substructure search
given fewer hits than I expected?
You may have drawn your substructure with incorrect bond types. The CSD uses a number of conventions for bond types;
for example, the six C-C bonds in benzene all have the aromatic bond type, but thiophene is drawn with single and double bonds.
In addition, the CCDC is careful to ensure that CSD entries reflect the structural details specified by the original author. Therefore, bonding conventions for
a particular substructure may not be consistent throughout the database. In this case, variable bond types should be used to increase the range of possibilities.
Indeed the pattern of connected atoms in a substructure is sometimes so distinctive that the Any bond type can be used, at least for initial searches.
Alternatively, perhaps you've drawn a different tautomeric form to the authors representation.
Why has my author-name
search given fewer hits than I expected
?
It is easy to miss hits unless you understand the CSD conventions for Authors' Names. In particular please be aware that:
Authors don't always give their name in the same way, e.g. A.Smith and A.B.Smith; C.Kratky and Ch.Kratky
Cyrillic characters are not always transliterated the same way, e.g. Belskii and Belskij
Chinese names are most often given in full, sometimes with the given name first, sometimes with the family name first and sometimes initialised
American surnames often contain dynastic tags, e.g. a search for Jones will not find Jones Junior if the Exact surname option is used
Why has my compound name
search given some unexpected hits?
It's very hard to devise a compound-name search that will allow for all the possible ways in which a compound may be named. Try using name roots (e.g. thiazol rather than thiazolyl)
or, if at all possible, do a substructure search instead. The advantage of compound-name searching is
that it's usually quicker to type a name than to draw a substructure. Please be aware that it is
not yet possible to exclusively search for an exact compound name since a search for an exact name will also
retrieve all hits in which the compound name you specified is included, so, for example, a search
for ferrocene will also retrieve acetyl-ferrocene.
What is the best way of
reducing the number of hits if a search gives more than I want?
You could simply stop the search before it's finished. However, a less arbitrary method is to make the search query more specific.
Alternatively, you can restrict the search to only the most experimentally precise structures, e.g. by setting an upper limit on the R-factor by selecting the appropriate filter within the Search Setup dialog.
It is also possible to restrict the search to Only Organics or Only Organometallics, depending on your area of interest.
Can I search on
CSD refcodes within ConQuest?
Each CSD entry is identified by a unique Refcode (entry ID) comprising six letters. Some entries also include two digits
which identify additional structure determinations,
for example, ABACOF03. To retrieve an entry whose Refcode is known simply hit the Refcode (entry ID) button in
Build Queries and type the required Refcode into the input box.
It is also possible to search for all occurrences of a particular refcode, for example, to retrieve all structures where the first six
letters of the refcode are GLYCIN. Type GLYCIN into the input box and ensure that the Find all Refcodes that
begin with query text option is selected.
Note: Due to the way in which Refcodes are assigned, it
is not valid to search the CSD using refcode ranges.
Why is my search taking so
long?
This is probably due to limitations in the CSD search engine. The most common types of slow searches are:
Substructure searches for groups that contain symmetry (e.g. t-butyl); these can take a very long time indeed, especially if 3D parameters are being calculated.
Substructure searches for groups that contain only the most common elements (C,N,O) and are connected by single or Any bond types.
Substructure searches for large (>12-membered) rings, especially if they are carbocyclic.
Searches for nonbonded interactions especially for patterns involving more than one interaction.
Some text searches.
How do I tabulate geometric
parameters after a search has been run?
Any geometric parameters you want tabulated must be specified in the draw window before the search is run. Defined parameters can then
be exported to either VISTA or Excel for further analysis by hitting the Analyse Hitlist button and then selecting the appropriate View in button.
Can I search my own private
database using ConQuest?
Yes, ConQuest can be used search in-house databases in addition to the main CSD.
Private databases can be created using the PreQuest program which is distributed as part of the CSD System Software.
If you have created an inhouse database that you wish to search using ConQuest you must first activate it using the procedure described in the CSD System Installation Notes.
Can I use ConQuest for
teaching?
Yes, ConQuest includes Classroom ConQuest which is a version of ConQuest that has been designed for group teaching activities.
Anyone with at least one normal ConQuest licence can install as many copies of Classroom ConQuest as they require. Classroom ConQuest
has all the functionality of normal ConQuest with the limitation that searches can only be done on a subset of CSD entries. For further information on how to install Classroom ConQuest please see the CSD System Installation Notes.
Is it possible to specify
stereochemical configuration when constructing a query using the sketcher?
The 2D representations of structures in the database only contain information concerning connectivity of atoms, no stereochemical information is given in these diagrams. As a result, it is not possible to sketch a query in terms of 'up and down' or 'dark filled/dashed line' bond representation.
Absolute stereochemistry is included in the CSD but only when the information is provided by the author in the original publication. When included in the database absolute configuration must have been determined using one of the following methods:
Anomalous dispersion (Bijvoet pairs, Friedel pairs, Hamilton test, R-factor ratio, eta refinement or Rogers' eta parameter; the parameter is not recorded)
Internal comparison
Refinement of the Flack parameter (no value of the parameter or reference to use of the Flack parameter is recorded)
When present, information relating to stereochemistry is given within the compound name under the Chemical tab. In addition, if the absolute configuration of the structure has been determined, then the entry will also include the phrase absolute configuration under the chemical tab.
I know that a particular
crystal
structure has been published, why is it not included in the latest release of the database?
Although the crystal structure has been published we may still be waiting for the supplementary data in order to process the structure into the CSD.
The deadline date for entries being archived into the CSD is 2 months prior to the release date, to allow for compilation of the database and for software testing,
so your structure of interest may have been processed but missed the deadline date for a particular release of the CSD.
The CSD is released in November of each year, it is also possible to download CSD data updates at regular intervals. This will keep your copy of the CSD more current between each major release of the CSD System, see:
CSD updates.
If you think your structure of interest has missed the deadline
date and need the data for your work then please contact:
with as much detail as possible so that we can identify and retrieve your requested crystal structure.
I've found an entry in the CSD
which either contains an error or does not correctly reflect the original publication. Who should I notify?
In excess of 30,000 structures are added annually to the Cambridge Structural
Database and while every effort is made by the team of Scientific Editors to
check the data against the published material and supplementary data, errors
do occur. The information stored in the CSD is continually being updated and
we are always pleased to receive corrections or amendments to existing
CSD entries. The corrections will be carried out immediately but they will not
be available to you until you receive your next CSD System release.
Please email details of any errors to:
Misprints in papers are corrected without reference to the author, but we will
not enter into correspondence with regard to different interpretations of data.
Any such comment should be carried out directly between the enquirer and the author.
I'm using the porphyrin template
provided with ConQuest as part of my substructure but the search seems to be missing hits I know are there: what is going on?
Although the templates provided within ConQuest are intended to represent 2D substructures as stored in the CSD, porphyrin is
unfortunately a special case as it is difficult to represent all the resonance forms with a single template.
Using the template as given in ConQuest will retrieve the majority of porphyrin hits however it may miss cases where
some of the bonds are aromatic. To avoid this issue, the porphyrin template bonds should be re-typed as Any. The
template can then be re-saved: full instructions on how to do this can be found in the
ConQuest documentation.
How can I search on tautomers with ConQuest?
In tautomeric situations, the crystal structure will contain a
specific tautomer and the safe procedure is to formulate the principal
tautomers and search for them all. An example strategy which will retrieve tautomeric structures aminoacridine is available:
I find searching for polymeric
structures difficult and I get results I don't fully
understand. Can you explain how polymeric structures are
defined so I can tailor my searches to be more effective?
Polymers and extended structures are defined within the CSD with the use
of the polymeric bond type. We have prepared a document that details how
to search for polymeric structures via the polymeric bond type which can
be viewed by clicking the following link:
.
